Add built in invoker

License: MIT
Signed-off-by: Jakub Sztandera <kubuxu@protonmail.ch>

chain/invoker.go

@@ -0,0 +1,140 @@
+package chain
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"strconv"
+	"strings"
+
+	"github.com/ipfs/go-cid"
+)
+
+type invoker struct {
+	builtInCode map[cid.Cid]nativeCode
+}
+
+type invokeFunc func(act *Actor, vmctx *VMContext, params []byte) (InvokeRet, error)
+type nativeCode []invokeFunc
+type InvokeRet struct {
+	result     []byte
+	returnCode byte
+}
+
+func newInvoker() *invoker {
+	inv := &invoker{
+		builtInCode: make(map[cid.Cid]nativeCode),
+	}
+	// add builtInCode using: register(cid, singleton)
+	return inv
+}
+
+func (inv *invoker) Invoke(act *Actor, vmctx *VMContext, method uint64, params []byte) (InvokeRet, error) {
+
+	code, ok := inv.builtInCode[act.Code]
+	if !ok {
+		return InvokeRet{}, errors.New("no code for actor")
+	}
+	if method >= uint64(len(code)) || code[method] == nil {
+		return InvokeRet{}, fmt.Errorf("no method %d on actor", method)
+	}
+	return code[method](act, vmctx, params)
+
+}
+
+func (inv *invoker) register(c cid.Cid, instance interface{}) {
+	code, err := inv.transform(instance)
+	if err != nil {
+		panic(err)
+	}
+	inv.builtInCode[c] = code
+}
+
+type unmarshalCBOR interface {
+	UnmarshalCBOR([]byte) (int, error)
+}
+
+var tUnmarhsalCBOR = reflect.TypeOf((*unmarshalCBOR)(nil)).Elem()
+var tError = reflect.TypeOf((*error)(nil)).Elem()
+
+func (_ *invoker) transform(instance interface{}) (nativeCode, error) {
+	itype := reflect.TypeOf(instance)
+	newErr := func(str string) error {
+		return fmt.Errorf("transform(%s): %s", itype.Name(), str)
+
+	}
+	var maxn uint64
+	invokes := make(map[uint64]reflect.Method)
+	for i := 0; i < itype.NumMethod(); i++ {
+		meth := itype.Method(i)
+		if !strings.HasPrefix(meth.Name, "Invoke") {
+			continue
+		}
+		sid := strings.TrimLeftFunc(meth.Name, func(r rune) bool {
+			return r < '0' || r > '9'
+		})
+
+		id, err := strconv.ParseUint(sid, 10, 64)
+		if err != nil {
+			return nil, err
+		}
+
+		t := meth.Type
+		if t.NumIn() != 4 {
+			return nil, newErr("wrong number of inputs should be: " +
+				"*Actor, *VMContext, <type of parameter>")
+		}
+		if t.In(0) != itype {
+			return nil, newErr("passed instance is not struct")
+		}
+		if t.In(1) != reflect.TypeOf(&Actor{}) {
+			return nil, newErr("first arguemnt should be *Actor")
+		}
+		if t.In(2) != reflect.TypeOf(&VMContext{}) {
+			return nil, newErr("second argument should be *VMContext")
+		}
+
+		if !t.In(3).Implements(tUnmarhsalCBOR) {
+			return nil, newErr("paramter doesn't implement UnmarshalCBOR")
+		}
+
+		if t.In(3).Kind() != reflect.Ptr {
+			return nil, newErr("paramter has to be a pointer")
+		}
+
+		if t.NumOut() != 2 {
+			return nil, newErr("wrong number of outputs should be: " +
+				"(InvokeRet, error)")
+		}
+		if t.Out(0) != reflect.TypeOf(InvokeRet{}) {
+			return nil, newErr("first output should be of type InvokeRet")
+		}
+		if !t.Out(1).Implements(tError) {
+			return nil, newErr("second output should be error type")
+		}
+
+		if id > maxn {
+			maxn = id
+		}
+		if _, has := invokes[id]; has {
+			return nil, newErr(fmt.Sprintf("repeated method=%s id: %d", meth.Name, id))
+		}
+		invokes[id] = meth
+	}
+	code := make(nativeCode, maxn+1)
+	_ = code
+	for id, meth := range invokes {
+		code[id] = reflect.MakeFunc(reflect.TypeOf((invokeFunc)(nil)),
+			func(in []reflect.Value) []reflect.Value {
+				paramT := meth.Type.In(3).Elem()
+				param := reflect.New(paramT)
+
+				param.Interface().(unmarshalCBOR).UnmarshalCBOR(in[2].Interface().([]byte))
+				return meth.Func.Call([]reflect.Value{
+					reflect.ValueOf(instance), in[0], in[1], param,
+				})
+			}).Interface().(invokeFunc)
+
+	}
+	return code, nil
+}

chain/invoker_test.go

@@ -0,0 +1,43 @@
+package chain
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type basicContract struct{}
+type basicParams struct {
+	b byte
+}
+
+func (b *basicParams) UnmarshalCBOR(in []byte) (int, error) {
+	b.b = in[0]
+	return 1, nil
+}
+
+func (_ basicContract) InvokeSomething0(act *Actor, vmctx *VMContext,
+	params *basicParams) (InvokeRet, error) {
+	return InvokeRet{
+		returnCode: params.b,
+	}, nil
+}
+func (_ basicContract) InvokeSomething10(act *Actor, vmctx *VMContext,
+	params *basicParams) (InvokeRet, error) {
+	return InvokeRet{
+		returnCode: params.b,
+	}, nil
+}
+
+func TestInvokerBasic(t *testing.T) {
+	inv := invoker{}
+	code, err := inv.transform(basicContract{})
+	assert.NoError(t, err)
+	ret, err := code[0](nil, nil, []byte{1})
+	assert.NoError(t, err)
+	assert.Equal(t, byte(1), ret.returnCode, "return code should be 1")
+
+	ret, err = code[10](nil, nil, []byte{1})
+	assert.NoError(t, err)
+	assert.Equal(t, byte(1), ret.returnCode, "return code should be 1")
+}

chain/vm.go

@@ -68,6 +68,7 @@ type VM struct {
 	buf         *bufbstore.BufferedBS
 	blockHeight uint64
 	blockMiner  address.Address
+	inv         *invoker
 }
 
 func NewVM(base cid.Cid, height uint64, maddr address.Address, cs *ChainStore) (*VM, error) {
@@ -206,4 +207,9 @@ func (vm *VM) TransferFunds(from, to address.Address, amt BigInt) error {
 
 func (vm *VM) Invoke(act *Actor, vmctx *VMContext, method uint64, params []byte) ([]byte, byte, error) {
 	panic("Implement me")
+	ret, err := vm.inv.Invoke(act, vmctx, method, params)
+	if err != nil {
+		return nil, 0, err
+	}
+	return ret.result, ret.returnCode, nil
 }